This may sound silly, but with specific regards to the walking toddlers, I tend to suggest some form of 'fire snake' that the kids can have fun making, and when it comes to the evacuation all the kids hold on to the snake they made and follow a member of staff out, with a member of staff keeping an eye on the back of the 'snake'. (or one of the older more well behaved kids who could alert a member of staff if another child lets go) If staff treat the drills as a bit of a game then the kids tend to happily play along. That will release some of the staff that are designated to look ater the toddlers free to help evacuate the babies. And as Kurnal said, cots on wheels help.
From ofsted:
Day Nurseries
Minimum staffing ratios (this includes children of staff and volunteers)
1 member of staff for every 3 children under 2 years old
1 member of staff for every 4 children aged 2 years old
1 member of staff for every 8 children aged 3 to 7 years old
50 toddlers = 7 staff (Although some may be under 2 and walking)
25 Babies = 9 staff
Example of how it can help:
17 kids to each "snake", One member of staff at the front of the snake holding a baby, one at the rear holding a baby and ensuring nobody leaves the snake. 3 snakes use maximum 6 staff and also take 6 babies.
Leaves 19 babies for 10 staff. Much more manageable than 3 babies per person.
It's not perfect, and it would take alot of practice, but sometimes you have to make the best of a bad job. The "snake" can also have specific sections to be held, and can help in a roll call and to keep the kids orderly once outside. (They are already in a line up of sorts.)
I am sure someone will find problems with it, and I would be glad of any constructive suggestions that could be passed on to these facilities.
I would also concentrate on extinguisher training for staff to ensure any problem is dealt with in the early stages. People in these facilities always go for the 'everybody out immediately' approach and therefore do not think about staff training on FFE. But good procedures with one or two persons nominated to tackle any small fire could avert a serious incident. Due to the time an evac would take there is plenty of time for the fire to be attacked while everything else is getting into motion.